Cultivate your knowledge tree: A foundational approach to learning

8 min readFeb 19, 2024

The metaphor of knowledge as a tree is profoundly fitting. Fundamental knowledge, much like the trunk of a tree, is crucial for branching out and harvesting the fruits of your educational journey.

Ez-Zitouna — oldest university?

Did you know this piece of trivia? Ez-Zitouna, predating Oxford University by over three centuries, may very well be the oldest university in continuous operation.

Oldest university in continuous operation?

The subject of what constitutes the oldest “university” is controversial and hinges on how one defines the term. This issue is explored in a post on the “Renaissance Mathematicus” blog and was of course heatedly debated on social media. Across the globe, numerous other centers of learning could lay claim to this title. But if this is your first time hearing about Ez-Zitouna, it probably comes as a surprise, challenging the prevailing narratives.

In recent times, we observe a disturbing rise of blatant Islamophobia, along with antisemitism and other fascist tendencies against various minority groups. In this context, historical perspectives become particularly valuable. Popular culture, often dominated by stereotypical portrayals and simplistic ‘us vs. them’ narratives, tends to obscure the barbaric actions of Westerners in relatively recent history, actions that some would argue continue in ongoing wars.

Despite considering myself well-informed on such matters, I was recently taken aback to discover that the term ‘vandals’ originated from a group of Germanic tribes. These tribes were notorious for their invasions across Southern Europe and North Africa, particularly gaining infamy after their sacking of Rome. Check the map. Basically, the Vandals were just a bunch of German illegal immigrants.

The Vandals — wandering Germanic people.

Historical insights like these can provide a useful perspective of our present and past. This isn’t an attempt to overlook the current and multiple shortcomings of Muslim countries. However, consider this: examine all the instances of #Islamophobia that you come across on X / Twitter and elsewhere, and imagine replacing ‘Islam’ with ‘Christianity’ or ‘Judaism’. How would that narrative change? This form of reflection works both ways and serves as a personal measure for me to maintain my sense of humanity and decency. It’s a valuable exercise in empathy and fairness, reminding us to consider different perspectives and the impact of our words and actions.

Ez-Zitouna — the olive tree

Having gotten these thoughts off my chest, let’s return to the main topic. ‘Zitouna’ in Arabic translates to ‘olive,’ and Ez-Zitouna means “The Olive Tree” in colloquial Tunisian Arabic. How remarkable is it that one of the oldest universities is named after a plant? And it’s even more fitting that this institution bears the name of a tree symbolizing strength and longevity, encapsulating the essence and enduring legacy of Ez-Zitouna.

This name resonates with me deeply due to my family’s connection to the olive tree Olea europaea. As mentioned in a previous post, in the early 20th century, my great-grandfather Mohamed Said Kamoun (1868–1945) was awarded prestigious accolades and medals at agricultural expos in France for the olive oil produced on his farm in the Sfax region of central Tunisia. Honoring this heritage, I continue to be an avid consumer of olive oil, not only because it tastes incredible but also because it’s a cornerstone of the Mediterranean diet, which UNESCO has recognized as an Intangible Cultural Heritage of Humanity. For a taste of #MedFood #TunFood, check out my posts on X / Twitter.

M. Said Kamoun’s medals for his olive oil at agricultural expos in France: 1911 Bronze medal in Roubaix and 1924 Gold medal in Paris. Source: Maher Kamoun.

The tree of knowledge

A few years ago, Erin Zess, a PhD student in my lab, drew a parallel in an essay between core knowledge and a tree trunk. She highlighted this great quote:

“I’ve heard people compare knowledge of a topic to a tree. If you don’t fully get it, it’s like a tree in your head with no trunk. Without a trunk, when you learn something new about a topic — a new branch or leaf of the tree — there’s nothing for it to hang onto, so it just falls away.” Tim Urban, ‘Wait But Why’ blog

The metaphor of knowledge as a tree is profoundly fitting, a fact undoubtedly recognized by the founders of Ez-Zitouna. The core knowledge forms the trunk — an essential foundation. From this trunk, branches, leaves, and fruits emerge, symbolizing the diverse, specialized areas of knowledge that develop from a strong fundamental base. Only when the tree is fully grown and nurtured does it yield its harvest.

Basking in the glory of M. Said Kamoun’s award-winning olive oil, crafted from the majestic Chemlali olive trees of Sfax. Photo by Chiraz Khrouf / Ridha Kamoun.

The branches, leaves, and fruits may change with each season, but without the trunk, the tree ceases to exist. Similarly, in the realm of scientific knowledge, before we consider any application, there must be a fundamental understanding of key disciplines and concepts. It’s these basics that sprout branches and offshoots, allowing the application of knowledge to benefit society.

This crucial aspect is often missed in the approach to problem-driven science. In many countries, there’s a heavy focus on applications, and biologists are increasingly trained like engineers or biotechnologists. They learn practical skills, but the question remains — are they really grounded in the basics?

Government and funding bodies frequently prioritize the societal benefits of science. However, before we can address how science helps society, we need to establish a solid foundation — the trunk. Our students need a robust, trunk-like base in scientific knowledge to apply their learning effectively. For instance, if we aim to solve the impact of climate change-induced drought on wheat or olive cultivation, our first investment should be in basic life and agricultural science. With this foundation, scientists will be better equipped to tackle specific problems and deliver impactful applications.

To cite an example that I recently discussed, I remain puzzled at how many molecular biologists seem to underappreciate the science of evolution, especially now that, in this post-genomic era, molecular evolution has become central to understanding, interpreting, and exploiting genomic data. Similarly, this issue is mirrored among some evolutionary biologists who underappreciate the importance of molecular genetics and the centrality of DNA in understanding how living organisms evolve. Perhaps this is due to the type of life science curriculum they have taken, which often misses key disciplines.

If you are a biologist, you cannot ignore DNA, evolution, and biodiversity. These form your trunk, the core fundamental knowledge from which branches, leaves, and fruits — your specialized knowledge and contributions — can grow.

DNA, evolution, and biodiversity in the style of Vincent Van Gogh. Credit: ChatGPT.

Build your knowledge tree

Embarking on the journey of building your knowledge tree is an essential endeavor for any aspiring scientist or learner. Here’s some advice on how to cultivate this vital foundation:

Start with the trunk: make sure to cover the fundamentals Begin by concentrating on the core principles and theories of your field. Be generous in your learning, and don’t shy away from topics and disciplines that may at first seem unrelated to your focus. This foundational knowledge forms the trunk of your tree, providing the necessary support for all future growth. Make sure you have a strong grasp of the basics before branching out into more specialized areas.

Produce deep roots: stick to your principlesA tree is anchored by its roots. Similarly, you need to develop a deep root network to remain grounded and true to yourself. Reflect deeply on what you aim to achieve in both your work and life, and identify your foundational principles. Commit to these principles. They will serve as your compass and provide support through challenging times.

Branch out: don’t hyperspecializeOnce your trunk is sturdy, start exploring the branches of your tree, which symbolize the specialized areas within your discipline. Embrace the opportunity to investigate various branches; such exploration will broaden your understanding and assist in pinpointing your areas of interest. Above all, don’t hyperspecialize. You rarely know what will be useful in the future, which branch will produce more fruits.

Grow leaves and fruits: produce tangible outcomes As your knowledge tree flourishes, you’ll start to grow leaves and fruits — the concrete results of your efforts and expertise. Make sure to bring your projects to completion. You may grow the most beautiful tree, but without fruits, there will be nothing to harvest. Remember, it often takes 95% of the effort to complete the last 5%. Being a closer requires special skill and dedication, essential for completing projects and transforming the fruits of your labor into a plentiful harvest.

Continuous nourishment: are you doing better than six months agoJust as a tree requires ongoing nourishment to thrive, so does your knowledge. Consider this a lifelong journey. Stay curious and keep learning. Attend workshops, seminars, and courses beyond your current expertise. Read extensively, and don’t shy away from new technologies or methodologies.

Prune when necessary: understand the concept of opportunity cost Just like a tree sometimes needs pruning to flourish, it’s essential to streamline and refine your activities. Recognize the benefits of foregoing certain tasks in favor of prioritizing others — this is the essence of opportunity cost. Your time is limited so spend it wisely.

Opportunity cost or appreciating that time is your most valuable asset.

Olive or Saguaro?

Some olive trees are awe-inspiring, having lived for thousands of years and still bearing fruit. Think of your scientific journey akin to an olive tree: the branches, leaves, and fruits all rely on a sturdy trunk and an expansive root network. Without the trunk and roots, producing a crop is impossible. Yet, if all the branches and leaves were lost, the tree could regrow, thanks to the foundational strength of its trunk and roots, allowing for resilience through tough times.

On the other hand, consider the saguaro, Carnegiea gigantea, a towering columnar cactus that can exceed 12 meters in height. This plant is another source of inspiration, growing slowly yet steadily, capable of enduring the harsh conditions of the desert and branching out occasionally. Its resilience and gradual growth under adverse conditions serve as a potent metaphor for persistence and adaptation.

I love diversity. Who’s ready for a Saguaro University?

The saguaro Carnegiea gigantea.


This article was inspired by discussions and exchanges with numerous colleagues. Erin Zess first brought to my attention the metaphor of basic knowledge as a tree trunk in an essay she wrote for the Norwich Research Park Institutes. The article was written with assistance from ChatGPT.

This article is available on a CC-BY license via Zenodo.

Cite as: Kamoun, S. (2024) Cultivate your knowledge tree: A foundational approach to learning. Zenodo




Biologist; passionate about science, plant pathogens, genomics, and evolution; open science advocate; loves travel, food, and sports; nomad and hunter-gatherer.